Question

The structures of beryllium chloride in the solid state and vapour phase, respectively are

Answer 1

The structures of beryllium chloride in the solid state and vapour phase, respectively are chain and dimeric. In vapour phase at above $1200\text{K}$, $BeC{l}_2$ is monomeric having a linear structure $Cl-Be-Cl$. The bonding in $BeC{l}_2$ is covalent and $Be$ atom accommodates 2 + 2 = 4 electrons in the two $sp-$ hybrid orbitals. Below $1200\text{K}$, beryllium chloride in vapour phase exists as a mixture of monomer $BeC{l}_2$ and dimer $B{e}_{2}C{l}_4$



The structure of $BeC{l}_2$ in solid-state is a polymeric chain structure and each $Be$ atom is surrounded by four $Cl$ atoms. Two $Cl$ atoms are covalently bonded and two are bonded by coordinate bonds.